A pulley system consists of a single movable pulley at the top and a 250 g weight. One end of the string is attached to the ceiling, and the string passes under the pulley, redirecting the force from downward to upward. At its relaxed state the weight rests on the ground. A steady upward pulling force is applied to the free end of the string, causing the weight to rise at a constant speed and then gradually stopped. After 0.5 seconds, the force is reduced so that the weight gently return to ground.